Today’s lesson is an introduction information about the Cisco routers. Before embarking on the study material, I want to congratulate everyone who watches my course, because the video “Day 1” is today viewed almost a million people. I thank all users who contributed to the study of the CCNA course.
Today we will explore three topics: a router as a physical device, a small introduction to Cisco routers and the initial configuration of the router. This slide illustrates how a typical router model Cisco 1921 production.
Unlike a switch, having a plurality of ports, a typical router has only 2 ports for the connection, in this case Gigabit Ethernet ports GE0/0 and GE/1 and the USB connector. The router also has slots for expansion modules and 2 console ports, including 1 USB port. A distinctive feature of the Cisco routers is the presence of a switch – a switch Cisco switches do not have. Usually front of the router is shown in the bottom left of the slide. On the back of the router there are sockets for cable connections. In this case, the cable from the slot GE0/0 or GE/1 connects to the switch.
Bottom right shows the expansion module NME-X-23-ES-1GP, which you insert into the router, removing the blanking panels. Using these modules, you can extend the capabilities of conventional Cisco router to suit your needs. As you know, the Cisco products because of their complexity and wide functionality is quite expensive, so the user has a possibility not to overpay for a device with more features than he needs. By purchasing a simple router for 2 ports, you can the development of networks to purchase the necessary modules. In General, the Cisco device is able to perform many functions. Routers was not invented by Cisco, but the router made Cisco the company that we know today. Cisco began mass production of routers with the highest quality, that provide this products a leading position in the market of network devices.
Cisco calls itself a software company, i.e. a company that produces software. Hardware, the same hardware Cisco can manufacture any manufacturer, for example, China, having bought the appropriate filling. But Cisco IOS software does device this company for what they really are. The company is truly proud of the operating system that runs on all Cisco devices – like switches and routers.
The most important invention is the Cisco technology Enhanced CEF, or Cisco Express Forwarding. It provides a very rapid transfer of data, virtually at the maximum speed, which allow the technical capabilities of the network. It became possible due to integrated circuits special purpose Cisco ASIC — Application Specific Iintegrated Сircuitry that cause the switch to forward packets at almost the speed of your network.
As I said, the router to a greater extent softwaree device, so routing decisions are taken by the operating system of Cisco IOS.
You know that there are expensive graphics cards for computer games. So, if you don’t have such a card, all the cumbersome calculations, 3D animation and complex graphics processing performs your operating system, loading the CPU. If you have a powerful video card with its own processor, the GPU and its memory, the gaming performance increases many times, because the graphics part is a separate “hardware”.
Similarly operates the switch, because all the decisions for packet switching are taken separate hardware without impacting the router in which these decisions would have to take software. Cisco uses a half-software, half-Chardonnay technology CEF, which forces the router to make fast routing decisions. This feature is unique to Cisco routers.
We have already discussed how to perform the initial configuration parameters of the switch, and since the router configuration is in a similar way, I’ll tell you about it very quickly. I open the program Cisco Packet Tracer and select the router model 1921, then open the console window IOS, where you can see how to load the operating system of this router.
You see that we have loaded version 15.1 is the latest version of IOS, memory set to 512 MB CISCO 2911, next are the rest of the operating system settings, the test image IOS, and of course, there is a license agreement, and other such things.
I’ll make a separate video devoted exclusively to Cisco IOS, or just talk about the different services of the operating system. Let me just say that the version number you can determine what features and functions the OS has. Starting with 15.1, all IOS versions are universal, that is, depending on the license, which is acquired by the user, it can use the various functions of the system. For example, if you need to provide enhanced network security, you buy a license of security service, if you need voice service license voice service, etc.
To version 15.1 routers had OS with different versions – Basic, Security, Enterprise, Voice Enable and so on. For example, a router my friend had the Enterprise version of IOS and I had a Basic version of IOS, while nothing prevented me to take the other version and install it on your router because Cisco did not use the concept of licenses of the OS.
Starting with version 15.1, the company began to apply the concept of licensing options, and until then, until you have acquired the appropriate key, you cannot use any additional services of the operating system. A little later, when we consider the licensing policy of Cisco, I will tell you about the different versions of IOS. Meantime don’t pay any attention to it and go straight to the log download.
At the end of the log you can see the description of “iron”, which started system: brand CPU, 3 Gigabit interface 64-bit DRAM, 256 KB non-volatile memory. This memory seems too little, but for the router receiving the routing solution, that is enough. This memory should not be compared with the memory of your computer, so it is absolutely different things.
Log download Cisco IOS ends with a question: “Continue with configuration dialog? Yes/No”. If you answer “Yes”, the system will guide you through a series of questions, answering which you complete the initial device configuration.
In the process of studying the CCNA course you don’t have to do this, so always answer “No” to this question. Of course, you can choose “Yes” and browse through the configuration, but since you don’t know how to do this, better choose the “No”answer.
Selecting “No” and press RETURN, we get to the prompts where you can type in various commands. As in the case of the switch, at the beginning of the dial command Router > enable to go into privileged mode. Then I type config t (configure terminal) and go to global configuration mode.
Let’s quickly run down the teams. I want to change the hostname, so use the command hostname R1, followed by the team of denial, so I asked to show me the interfaces of the router with the command do show ip interface brief. We see that the Gigabit Ethernet 0/0 is administratively down, so I use the command int gigabitEthernet 0/0 no shutdown. Afterwards, the port status changes to up. If we again look at the state of the interfaces on the router shows that the port status is “enabled”. The status of the Protocol remains in down position, because to our router, nothing connected, and with no traffic it is in a disabled state. But as soon as the port of the router receives the traffic, the Protocol will change the status to up.
Next you need to set a password on the console. To do this, I type commands line con 0, password console and do the show run, to ensure that the console password was set. Password verification will be done only after I enter the login command. Now a console port of the router is password protected.
I have already told you about the encryption of passwords. Imagine someone got access to the current configuration of this device. Because it is perfectly clear the set password, this person can easily steal it, to at any time go to the settings of the router and hack the system.
One way to enable password encryption is the use of the command service password-encryption. Because by default this command is used with negation and has no view no service password-encryption, password encryption is not performed. Let’s move to the global configuration mode, print the command service password encryption and press Enter. This command means that the system takes a text password that I set, and encrypts it.
Now, if you look at the current configuration with the command do show run and go to the password row, you can see that the password is the seventh type took the form of a random sequence of numbers. Now, if one of your colleagues will be able to look over your shoulder and see the password, it will be very difficult to remember this sequence. Thus, we created the first line of defense system security access.
But even if he manages to copy the password, go to settings and try to insert it in the line password, the system will not allow access to the settings, because this set of numbers is not the password, and its encrypted value. The correct password is the word console, and when I do enter, you will get access to the console port. Thus, even if someone copies these numbers, you still will not be able to access the device.
But actually we are wrong because all you need an attacker is to visit the website which make it easy to decrypt the password Cisco the seventh type. Just log on to website page to enter the copied numbers and you will get the decrypted password in our case is the word console. Now the hacker just copy the word, go back to your IOS settings and paste it in the query string of the password.
In this case, a simple function of the Enable Password does not provide the necessary security. The best way to provide protection is to use the command enable secret cisco. If you then look at the current configuration, you can see that the password value is now a set of the most different characters. In this case, used the fifth type of password Cisco.
To decrypt the password of this type online is impossible, so now the console of your device is fully secure.
Next you need to set a password for Telnet. For this I type the command line vty 0 4 that will allow you to use the router 5 people, and I enter the command telnet password. Now, if someone wants to connect to the router via Telnet, he will need to enter the password is the word telnet.
Next to the switch we have configured the IP address Management IP because the switch applies to the 2nd level of OSI. However, the router is the device 3rd level, and this means that each port on the router has its own IP address.
In the switch we passed to the VLAN1 settings or settings of any other network, in which it was necessary to register IP address. We created the virtual interfaces and assigned IP addresses. But in the case of a router the addresses you must assign the physical ports, so I enter the command config t int g0/0. Then I use command to assign an IP address exactly the same as was done in the case of VLAN, that is, enter the command ip address 10.1.1.1 255.255.255.0, and then dial the no shutdown.
If you now look at the port status, use the command do show int brief shows that the address 10.1.1.1 assigned to the Gigabit Ethernet interface 0/0. Thus we have configured IP address.
Next, we turn to the setup of a banner Logon Banner. Exactly the same as for switch, I use the command banner motd & I can then enter any text to any kind you like, for example, Welcome to NetworKing Router, emphasize the text “stars” and close it with the ampersand &.
Further, if you want to disable the port, use the Shutdown command. To save the settings use the command copy running-config startup-config. The current configuration can be viewed using the command show running conf, and to view the boot configuration, use the command show startup conf. Since we used a new device out of the box and booting the default settings, in response to a request to show the boot configuration, the system responds that it does not yet exist.
After entering the command copy running-config startup-config the system asks you to confirm that the overwritten file is the settings file boot system startup-config. After overwriting the boot configuration file I check it with the command show startup conf and see that now he repeats the parameter file of the current state of the device. Now, if I turn off the router and turn it on again, it will boot using the saved parameters.
Verification of the status of the router is best done using the command show int brief, you can also use the command show int, which will show the status of all ports. If you want to look at the status of a specific port, you can use the command show interface g0/0, then the system will show full statistics for this interface.
As I said, the most important part of the router is the routing table. Can be viewed using the show ip route command.
At the moment the table is empty, because our router is not connected any device. In the next video we will look at how to create a routing table using a variety of protocols, how does it fill when connecting new devices by using static routing or dynamic protocols. In the world of routers, the command show ip route is the most popular, because usually all the problems begin routing with a routing table.
This concludes our tutorial, as told everything that was planned for today. Many users are asking what is my interest when I record and upload these videos. I’m doing it in my spare time for free. Of course, you can send me money if you want. Many websites use my videos and ask money for it, but I don’t want to do with their listeners, and I promise that my lessons will never be paid.
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